Display omitted
•We measured fragmentation by fitting power laws of cumulative patch frequency over patch size.•The Korcak exponent enables scale breakpoints in a spatial structure to be found.•Such ...thresholds become new meaningful indicators of the underlying causes of fragmentation.•Large forest patches become very rare beyond a small (27–101 ha) area threshold.•Interpretations point to landscape as spatial memory of human pressure on forests.
This study quantifies patchiness of eight types of zonal forests in three biogeographic regions of mainland Spain (Atlantic, Alpine and Mediterranean) which together occupy 1,726,578 ha. Their dominant species and European Habitat Type codes (EU Directive 92/43 EEC) are: Fagus sylvatica (9120, 9130 and 9150), Quercus robur and Q. pyrenaica (9230), Q. suber (9330), Pinus uncinata (9430), P. nigra ssp. salzmannii (9530) and P. pinea (subset of 9540). We applied the Korcak’s exponent B, which describes a hyperbolic relationship between the cumulative frequency of the number of patches and their sizes. The objectives were: 1) detect possible patch size intervals in which B varies significantly, explicitly identifying area thresholds, and 2) contribute to development of a robust forest mass fragmentation indicator. Exponent B was found by segmented regression analysis. The vector data were extracted from a filtered version of the Spanish Forest Map 1:50,000 (1997–2006). After validating the procedure by applying it to a previously published dataset, we found that in all cases the patch size range could be split into two significant intervals around relatively small threshold areas of 27–101 ha. In the one on the left, the rate at which relatively large patches become less abundant was always very slow (B = 0.017–0.094). After this threshold had been passed, the rate increased abruptly (B = 1.100–2.590). Both this high fragmentation and its lack of parsimony were unexpected in zonal forest types. General interpretations converge to the coexistence of forest patches of different ages due to human pressure events.
Present study deals with the role of wetland for regulating greenhouse gases (GHG) particularly methane (CH4) emission and carbon (C) sequestration in mature Ganges deltaic environment. The annual ...total amount of emission and sequestration in wetlands of varying types was estimated along with the seasonal variation. Result showed that the streams were the highest emitter of CH4 followed by ox-bow lakes in all the seasons whereas the bheries (embanked pisciculture arresting tidal water) consistently exhibited the lowest average emission. The average sequestration of C was the highest in ox-bow lakes followed by marshes and mudflats. The average emission in monsoon season was 43% and 78% higher than the average emission of pre and post-monsoon seasons respectively. The yearly total emission was 8.01 × 103 ton and yearly total sequestration was estimated 908.98 × 103 ton. From the perspective of GHG regulation, the wetlands were found to yearly uptake four times higher carbon dioxide (CO2) than the CO2 equivalent (CO2e) of emitted CH4. After offsetting the fixation cost of emitted CH4, the yearly surplus sequestrated C in the wetlands of the entire region was worthy of 68.46 million US dollar (USD). So, wetland plays positive role for reducing greenhouse gas effect and associated temperature rise which is considered to be serious issue. Such result has made a good agreement on the debated issue of wetland CH4 emission and C sequestration and will encourage restoring wetland for even mediating GHG issue.
Display omitted
•Fungi and woody plant diversity showed inconsistent patterns among habitat types.•The major fungal functional groups showed similar richness patterns among habitats.•Woody plant alpha diversity was ...an important indicator of saprotrophic and pathogenic fungi.•Relationships between fungal and woody plant communities depended on habitat types.
The diversity patterns of macroorganisms (i.e., plants) among different habitats have been well documented, however, those of microorganisms (i.e., fungi) as well as the relationships between them are still unclear. Here, we tested whether and to what degree fungal diversity was related to habitat types and compared diversity patterns of woody plants and soil fungi. We carried out field investigations on soil fungi in different habitat types (i.e., valleys, foothills, hillsides, and hilltops) in a 25-ha karst broadleaf forest in Southwest China. The tree richness, Shannon index, and Simpson index significantly increased from valleys to hilltops. While the soil fungal N1 diversity (the exponential Shannon index) marginally increased toward valleys, fungal N0 (richness) and N2 (the inverse Simpson index) diversity exhibited significantly reduced and increased patterns, respectively, from valleys to hilltops. The major fungal functional groups (i.e., EcM, AM, saprotrophic, and pathogenic fungi) showed similar increasing richness patterns in valleys. Moreover, woody plant alpha diversity was an important indicator of fungal functional groups except for EcM and AM fungi. In addition, woody plants increased in species turnover rate (βSIM) from valleys to hilltops, while fungal species had a concave distribution. The patterns of nestedness (βSNE) for tree species decreased from valleys to hilltops, while the opposite was true for soil fungal species. Our findings indicated that the diversity patterns of woody plants and fungi were inconsistent among habitat types, and the relationships between fungal and woody plant communities depended on habitat types in the karst forest.
Summary
The metacommunity framework has shed light upon the significance of local and regional processes in shaping ecological communities. However, our knowledge is limited how landscape context ...(i.e. type and positioning of habitats) influences the structuring of metacommunities.
We examined the role of environmental selection (niche‐based species sorting), dispersal and drift (i.e. stochastic changes in species abundance) mechanisms on the structuring of fish metacommunities in riverscapes. We used a hierarchical design and examined metacommunity structuring (i) in individual running water habitat types, namely highland streams, lowland streams, highland rivers and lowland rivers; (ii) in landscape types, where patterns in highland and in lowland types were examined separately and (iii) at the level of the whole riverscape, where samples from all running water types were pooled. Elements of metacommunity structure (EMS) analysis, community–environmental relationships in redundancy analysis, and decay of community similarity with distance (distance decay) complemented with partial Mantel tests were used to reveal the mechanisms behind the observed patterns.
Both the EMS framework and community–environment relationships revealed the prevalent role of selection (niche‐based species sorting mechanisms) on fish metacommunity structuring, although stochastic variability also influenced the results. Metacommunity structures reflecting niche‐based mechanisms (Clementsian or quasi‐Clementsian) were observed at higher hierarchical levels (i.e. at the riverscape and the landscape type levels), while quasi‐Clementsian or random patterns were found within single running water types.
Distance decay relationships indicated that dispersal limitation did not clearly affect metacommunity structuring in any combination of running water types. Partial Mantel tests showed that some part of the variation in distance decay could be explained by the correlation between environmental variables and fish assemblage structure in some habitat types, which further suggests the importance of niche‐based mechanisms in metacommunity structuring.
Our study shows that different metacommunity structures can arise in a hierarchy of habitat types in riverscapes, and niche‐based species sorting mechanisms are more influential in their structuring than dispersal ones. Landscape classifications are useful for a better understanding of the structuring of metacommunities in both the freshwater and terrestrial realms.
Numerous anthropogenic stressors, such as habitat alteration and nutrient enrichment, affect coastal and marine ecosystems around the globe. An additional threat to these ecosystems is accidental oil ...pollution. The proactive planning of efficient oil spill response actions requires a firm understanding of the spatiotemporal distribution of ecological coastal values at stake, and how these values can be protected in case of an oil spill. In this paper, literature and expert knowledge regarding the life history attributes of coastal and marine species were used to build a sensitivity index to assess the differences in the potential of species and habitat types to be safeguarded from oil. The developed index prioritizes sensitive species and habitat types based on 1) their conservation value, 2) the oil-induced loss and recovery potential, and 3) the effectiveness of oil retention booms and protection sheets to safeguard these entities. The final sensitivity index compares the predicted difference in the state of populations and habitat types five years after an oil spill with and without protective actions. The higher the difference, the more worthwhile the management actions are. Hence, compared to other oil spill sensitivity and vulnerability indexes presented in the literature, the developed index considers the usefulness of protective measures explicitly. We apply the developed index to a case study area in the Northern Baltic Sea to demonstrate the approach. It is noteworthy that the developed index is applicable to other areas as well, as the approach is based on the biological attributes of species and habitat types instead of individual occurrences.
•A simple sensitivity index for conservation priority ranking is presented.•Coastal ecosystems should be safeguarded based on their conservation value, recovery potential, and the protection effectiveness.•The approach is based on the biological attributes of species and habitat types instead of individual occurrences.•The developed index considers the usefulness of protective measures explicitly.•A globally applicable approach to reduce the adverse effects of oil spills is presented.
The mapping of biodiversity on continental margins on landscape scales is highly relevant to marine spatial planning and conservation. Submarine canyons are widespread topographic features on ...continental and island margins that enhance benthic biomass across a range of oceanic provinces and productivity regimes. However, it remains unclear whether canyons enhance faunal biodiversity on landscape scales relevant to marine protected area (MPA) design. Furthermore, it is not known which physical attributes and heterogeneity metrics can provide good surrogates for large-scale mapping of canyon benthic biodiversity. To test mechanistic hypotheses evaluating the role of different canyon-landscape attributes in enhancing benthic biodiversity at different spatial scales we conducted 34 submersible dives in six submarine canyons and nearby slopes in the Hawaiian archipelago, sampling infaunal macrobenthos in a depth-stratified sampling design. We employed multivariate multiple regression models to evaluate sediment and topographic heterogeneity, canyon transverse profiles, and overall water mass variability as potential drivers of macrobenthic community structure and species richness. We find that variables related to habitat heterogeneity at medium (0.13km2) and large (15–33km2) spatial scales such as slope, backscatter reflectivity and canyon transverse profiles are often good predictors of macrobenthic biodiversity, explaining 16–30% of the variance. Particulate organic carbon (POC) flux and distance from shore are also important variables, implicating food supply as a major predictor of canyon biodiversity. Canyons off the high Main Hawaiian Islands (Oahu and Moloka'i) are significantly affected by organic enrichment, showing enhanced infaunal macrobenthos abundance, whereas this effect is imperceptible around the low Northwest Hawaiian Islands (Nihoa and Maro Reef). Variable canyon alpha-diversity and high rates of species turnover (beta-diversity), particularly for polychaetes, suggest that canyons play important roles in maintaining high levels of regional biodiversity in the extremely oligotrophic system of the North Pacific Subtropical Gyre. This information is of key importance to the process of MPA design, suggesting that canyon habitats be explicitly included in marine spatial planning.
This paper pertains to the habitats of the Grey Francolin Francolinus pondicerianus with specific reference to populations, habitat type, vegetation, foraging, impact of human dwellings, and probable ...threats to populations in 20 villages covering four northern districts of Tamil Nadu, India. A total of 252 individuals were enumerated. During the non-breeding season, birds move in small groups of 2–6. Of four habitats identified, the maximum number of 143 birds was observed foraging in grasslands, while 61 were seen in dry fallow agricultural lands, 37 in dry lakes/canals, and 11 in harvested fields. No significant association was observed between habitat type and bird behaviour. They feed on termites and spilled paddy grains. Males have repeated loud calls and fight with each other. Four species of tall grasses, six of stunted trees and two shrubs were identified to provide bird habitat. Birds preferred to live away from human dwellings, with 193 found 1,000 m away from settlements. The study area continues to be a suitable habitat for Grey Francolin populations, hence this habitat needs protection.
This study was conducted between June 2017 and December 2018 to assess the bird community structure, diversity, feeding guilds, and the residential status of birds in Gautam Buddha Wildlife Sanctuary ...(GBWS). Avian diversity and guild organization in five different habitat types were classified according to the forest type present in the landscape. The results indicated a total of 99 avifauna that belongs to 48 families, distributed in 16 orders. Among the 99 species, 77 were residents, 17 were winter visitors, four were summer visitors, and only one was a passage migrant. Based on the feeding guild evaluation, the majority were insectivorous (47%), followed by omnivorous (24%), carnivorous (14%), granivorous (8%), frugivorous (4%), insectivorous (1%), and piscivorous (1%). The scrubland, among other forest types, represented the highest diversity value for the Shannon-Weiner diversity index (3.2), evenness was recorded highest in riverine habitat (0.63), whereas utmost Simpson’s dominance (0.98) and Fisher’s index value (41) were in human settlement. These findings of our study illustrate the outstanding potential of GBWS as an important protected site for mixed bird diversity and specific feeding guilds, precisely in terms of the insectivorous and omnivorous communities. Hence, the study outcomes set a notable landmark for understanding birds and their habitats.
This study estimates chemical composition of microplastic in sediments and benthic detritivores (sea cucumbers) collected from different marine rocky bottom habitat types (bank, landslide, cliff) of ...Salina Island (Aeolian Archipelago, Italy). Also, species richness and bottom coverings by benthic species were recorded at each sampling station. Correlations among chemical composition of microplastic in sediments and in detritivores were explored linking recorded variability to the factor “habitat type”. Results evidence that the habitat types considered in this study are characterized by wide species richness and by high percentages of bottom coverage by protected species by international conventions. In spite of the high ecological value of habitats considered in this study, microplastics were recorded both in sediments (PVC, PET, PE, PS, PA, PP) and in stomach contents of sea cucumbers (PET, PA) collected in all sampling sites, confirming the exposure of benthic species to microplastic pollution.
•Cliff, slide and banks from Salina Island showed a wide species richness.•MPs were recorded in sediment and holothurians from such habitat types.•MPs items recorded were PVC, PET, PE, PS, PA, PP.•The exposure of benthic species to MPs pollution was confirmed.
The Mediterranean Sea supports high levels of biodiversity and complexity but is facing increasing human pressures, so that strategies to protect and recover its ecosystems must be a priority in ...environmental policies. Benthic cartography represents the first step of marine spatial planning for the proper management and protection of our sea. Univocal habitat classification systems are thus needed to map, monitor, and inventory marine habitats, and to guarantee common and shared frames for a harmonized interpretation of the Mediterranean habitat types. In this paper we reviewed the existing classification systems of marine benthic habitats, to discuss the process of revision and updating of one of the first system developed under the Barcelona Convention (BC) in 1998 and adopted by all the Mediterranean countries. The BC classification was revised including the new habitats discovered in the last 30 years, and consistently with the criteria used to revise the EUropean Nature Information System (EUNIS), which is a comprehensive pan-European system for habitat identification. The updated BC classification is hierarchical with 5 levels, which allows representing the most suitable habitat level with respect to the restitution scale of the map. Each habitat is univocally identified by an alpha-numeric code, name and general description following the bionomic approach traditionally adopted in the Mediterranean benthic cartography since the late nineteen century. The new BC classification lists 128 main habitats up to the level 4, which may also contain sub-habitats at the level 5, i.e. associations and facies, totalising 394 habitat types (54% of new habitats with respect to the first BC classification). The updated BC classification system has been used for the selection of reference marine habitats that support two fundamental processes of environmental management: i) identification of Specially Marine Protected Areas according to the SPA/BD Protocol of Barcelona Convention; ii) selection of habitats to be monitored, as requested by the Integrated Monitoring and Assessment Programme and the European Directives (e.g., Water Framework and Marine Strategy). The new list of reference habitats, selected because of their high ecological and conservation value, contains 267 habitats, corresponding to 68% of the total habitats listed in the updated BC classification.
•Standardised classifications are needed to map and monitor marine habitats.•Existing classifications of marine habitats of the Mediterranean are reviewed.•The Barcelona Convention (BC) classification was fully revised and updated.•The new classification lists 394 habitat types, adding up 54% new habitats.•267 reference marine habitats were selected for conservation and monitoring.
PDF
